Since it's a pretty complicated setup I'd arrange for a good audio or home theater technician to come in and design then implement a solution for you.
I am a user of two hearing aids and use a siemens mini tek
and a blue tooth transmitter to connect to the mini tek form the bakc of the tv
The bluetooth transmitter streams sound to my blue tooth streamer aka mini tek directly to my hearing aids. I have my own personal surround sound and can have the tv volume appropriate to my needs and normal hearing people can set the volume at a different level.
I have the bluetooth transmitter plugged into a scart adpter at the back of the tv. and it transmits the Tv source sound excellently. When I chnage the tv source to HDMI one which is a bt vision box, sound form the box is heard through the tv speakers but through my blue tooth transmitter I get the TV source.
The only solution I have to this is to plug the bluetooth transmitter into the back of the BT vision box. This is frustrating as I have to move the TV table to do this.
If I pug the bluetooth transmitter into the earphone jack when I siwtch the sound source I get the sound swithced, but no one else in the room can hear the TV.
Is there a way of switching the sound source? My previous TV went from TV to AV1 soutce no problem. I hope this makes sense, my smart Tv does not appear to be as smart as it can be.
I hope this makes sense. Can any one offer a solution?